The present invention relates generally to the continuous separation of solid particles, such as soot, from a fluid, such as oil, by the use of a centrifugal field. More particularly the present invention relates to the use of a cone (disk) stack centrifuge configuration within a centrifuge assembly with a base that redirects the residual velocity of fluid discharge from the rotor jet nozzles to assist drainage rate and reduce pooling of oil in the centrifuge base.
Diesel engines are designed with relatively sophisticated air and fuel filters (cleaners) in an effort to keep dirt and debris out of the engine. Even with these air and fuel cleaners, dirt and debris, including engine-generated wear debris, will find a way into the lubricating oil of the engine. The result is wear on critical engine components and if this condition is left unsolved or not remedied, engine failure. For this reason, many engines are designed with full flow oil filters that continually clean the oil as it circulates between the lubricant sump and engine parts.
There are a number of design constraints and considerations for such full flow filters, and typically these constraints mean that such filters can only remove those dirt particles that are in the range of 10 microns or larger. While removal of particles of this size may prevent a catastrophic failure, harmful wear will still be caused by smaller particles of dirt that get into and remain in the oil. In order to try and address the concern over small particles, designers have gone to bypass filtering systems which filter a predetermined percentage of the total oil flow. The combination of a full flow filter in conjunction with a bypass filter reduces engine wear to an acceptable level, but not to the desired level. Since bypass filters may be able to trap particles less then approximately 10 microns, the combination of a full flow filter and bypass filter offers a substantial improvement over the use of only a full flow filter.
While centrifuge cleaners can be configured in a variety of ways as represented by the earlier designs of others, one product which is representative of part of the early design evolution is the Spinner II(copyright) oil cleaning centrifuge made by Glacier Metal Company Ltd., of Somerset, Ilminister, United Kingdom, and offered by T.F. Hudgins, Incorporated, of Houston, Tex. Various advances and improvements to the Spinner II(copyright) product are represented by U.S. Pat. Nos. 5,575,912; 5,637,217; 6,017,300; and 6,019,717 issued to Herman Nov. 19, 1996; Jun. 10, 1997; Jan. 25, 2000; and Feb. 1, 2000, respectively. These four patents are expressly incorporated by reference herein for their entire disclosures.
Hero-turbine centrifuges, as commonly used as bypass separators on diesel engine lube systems, operate by ejecting a high velocity fluid jet from a nozzle, which drives the centrifuge rotor via reaction force. After ejection from the centrifuge rotor, the fluid must be quickly evacuated from the centrifuge base and drained back to the sump. If the fluid begins to pool in the base, a condition known as flooding can occur, whereby the fluid contacts the turbine ends of the centrifuge rotor and dramatically slows down the speed of rotation. In this flooded condition, the centrifuge is rendered useless since it is no longer spinning at the desired speed and separating particulate from the oil. This condition is usually avoided by designing a very large outlet drain and providing enough head space beneath the rotor to allow some pooling to occur without the oil contacting the rotor.
The need therefore exists for a design that reduces the necessary size of outlet drain or reduces the required head space beneath the rotor, thereby allowing more room for rotor sludge capacity. The present invention meets this need in a novel and non-obvious way.
One aspect of the invention described herein is providing a centrifuge base with means for redirecting the residual velocity of fluid discharge from the rotor jet nozzles from a tangential direction to a radial direction in order to assist drainage rate and reduce pooling of oil in the centrifuge base.
One form of the present invention contemplates a centrifuge base with a radially directed gravity drain outlet configured with an outlet baffle oriented to redirect the residual fluid velocity in the radially outward direction of the drain outlet.
Another form of the present invention contemplates a centrifuge housing base having a central bottom drain where the base is equipped with spiral vanes to redirect the residual fluid velocity radially inward toward the drain outlet.
One object of the present invention is to provide a unique centrifuge base that assists the oil drainage rate and reduces pooling of oil in the base.